In rear projection televisions, high definition televisions and monitors, an image is projected from a light source, such as a liquid crystal display (LCD) or digital micromirror device (DMD), onto a transparent screen which typically utilizes a lenticular lens. The lenticular lens is a sheet or film having an array of lenticulae, or micro-lenses, on one side of the sheet. Generally, the opposite side of the sheet is substantially flat. The side of the lenticular lens faces the viewer and focuses the light projected from the light source so that the viewer sees an image on the lenticular lens. In televisions or monitors utilizing a lenticular lens, ambient light from the rear projected light source may reflect off of structures inside the television or monitor and become redirected toward the lenticular lens. This redirected light reduces the quality of the image because the redirected light may appear in places where the projected image should appear black. To achieve high contrast between the colored portion of the image and the black portion of the image, and to prevent the appearance of a Moiré pattern on the lenticular lens and the image, lenticular lenses used in rear projection televisions and monitors have typically included an opaque matrix, or aperture mask, designed to prevent ambient light from entering the projection television.
An opaque matrix may be prepared by printing an opaque, typically black, material on the flat surface of a lenticular lens in the areas corresponding to the areas of the lens where light from the rear light source is not focused by the array of lenticulae, and leaving transparent the areas where light will be focused by the array of lenticulae and viewed as an image. The transparent areas, known as apertures, are framed by the black material. One method of creating the aperture mask on the lenticular lens involves producing the opaque matrix first and then using that matrix to produce the lenticulae on the lenticular lens. Another method involves first preparing the lenticular lens and then using those lenticulae to produce the opaque matrix. The goal of these techniques is to ensure that the apertures of the matrix correspond to the locations where light will be focused by the lenticulae. The present invention relates to the second technique.
Other known methods have been used to create opaque matrices and transparent apertures on lenticular lenses. In one known method, an ultraviolet sensitive material is used to formulate an opaque matrix by exposing the material to ultraviolet radiation. Examples of this type of method can be found in U.S. Pat. No. 4,647,519 to Speigel, U.S. Pat. No. 4,666,248 to van de Ven and U.S. Pat. No. 5,870,224 to Saitoh, et al. In another known technique, a silver halide photographic light-sensitive material is used to create an opaque matrix by exposing silver halide photographic light-sensitive material to light. An example of this method is found in U.S. patent Publication No. 2003/0129,549 to Miyata, et al. In still another known technique, a thermally sensitive opaque material can create black stripes by exposing the thermally sensitive opaque material to a focused laser and heat. Examples of these methods can be found in U.S. Pat. No. 4,172,219 to Deml et al. and Japanese Patent Application No. 2000-378,258 to Watanabe, et al.